Ein is for masculine subjective nouns....ein hund frisst. Eine is for feminine nouns...eine frau isst. Einen is for masc. Nouns as objects...ich sehe einen hund. Took me a while to figure this out too. Same for der, die and den, respectively.

According to https://www.dictionary.com/browse/hound?s=t , a "hound" is primarily "one of any of several breeds of dogs trained to pursue game either by sight or by scent, especially one with a long face and large drooping ears."

That is, it's a particular kind of dog, one used for hunting. A chihuahua, for example, would not be a "hound".

For this reason, Duolingo does not accept "hound" as a translation of Hund.

"Der Hund" is a masculine noun. Therefore, in accusative form "Ein Hund" becomes, "Einen Hund". There is no such staff as accusative in English, but in German you have to specify "Who has the who". You have the dog, or dog has the you:) lol

There is such a thing as accusative in English if you learned you gramer in school. Any time the subjet of a sentance is acting on an other noun you are in accusative case. The boy shot the gun. Is accusative the boy is the subject to shot is the verb and the gun Is the derect object, or the thing the boy is acting in. In german all indenfinat articals attached to male object get an en added to them. I recomend doing some googleing about indefinat articals and accusative case. Also you shoild probly make some flash card with an english noun in one sid and der,die or das on the other to get down tje genderas color coting the gebders can also help. Knowing the gender of noun is very importat and there is no trick or patern and most are not logical so you just have to memerize them